1. Field of the Invention
The present invention relates to a stator for a rotary electric machine, and in particular to the structure for connection of coil conductors of the stator.
2. Description of Related Art
Electric motors that convert electric energy into rotational kinetic energy, electric generators that convert rotational kinetic energy into electric energy, and electric devices that function both as an electric motor and as an electric generator are known. Such electric devices are hereinafter referred to as “rotary electric machines”.
A rotary electric machine includes two members that are disposed coaxially to rotate relative to each other. Normally, one of the members is fixed, and the other member rotates. A coil is disposed on the fixed member (stator). The coil is supplied with electric power to generate a rotating magnetic field. The other member (rotor) is rotated through interaction with the magnetic field. The coil which is disposed on the stator is formed, for example, by mounting a plurality of partial coils on the stator and thereafter connecting the partial coils. To distinguish the individual coils before being connected from the entire coil after being connected, the former and the latter will hereinafter be referred to as “partial coils” and a “coil group”, respectively.
Japanese Patent Application Publication No. 2009-106008 (JP-2009-106008-A) discloses a stator for a rotary electric machine in which partial coils mounted on each of teeth of the stator are connected to each other by bus bars that are conductors that are different from coil conductors that form the partial coils. A plurality of bus bars are housed in a holding member to be integrated with each other to form a bus bar module. The coil conductor extends in the direction away from the partial coil. A part of the bus bar is disposed along the coil conductor. The respective distal ends of the coil conductor and the bus bar are welded to each other to connect between the partial coils.